Dwelling pitman



G. P. MALLORY.

DWELLING PITMAN.

APPLICATION FILED AUG-30. 1919.

1,378,706. Patented May 17,1921.

INVENTUR:

UNITED STATES PATENT OFF-ICE.

GEORGE r. MALLORY, or YORKLYN, DELAWARE, AssIoNoR, BY MESNE ASSIGN- MENTs, To SANITARY PRODUCTS CORPORATION OE AMERICA, or PHILADEL- PHIA, rENNsYLvANIA, A CORPORATION or VIRGINIA.

DWELLING PITMAN.

Specification of Letters Patent.

Patented May 17, 1921.

Application file-:1 August, 30, 1919. Serial No. 320,809.

of which the following is a specification,

reference being had therein to the accompanying draw ngs.

The invention relates to a new and useful improvement in dwelling pitmen. It is applicable to any press of the crank shaft type. It is especially intended for application to a press having upper and lower forming dies which are used for the form- Ingand sett ng of articles made of sheet material, although it is applicable to any press of the crank shaft type in which a dwell is desired after the two members of the press have come into Contact with each other. 7

it has been found in practice that what is known to the die-maker as a dwell between the upper and lower forming dies comprising a set is of great benefit in setting the piece to be formed, that is in case of material which has a tendency to spring away from the parts or dies over which they are formed. The momentary dwelling together with the upper and lower dies will cause the piece which is being formed to adhere more truly to the lines of the die. Thisis especially true of paper and of fiber products. Heretofore a cam has usually been employed to obtain this result but in a press in which this action is obtained by the use of a cam, the action is apt to be jerky and not smooth. One object of the present invention is to produce a dwelling pitman in which the action will be smooth and free from jerky movement, and also reducethe number of parts as well as expense.

The invention will be fully understood from the following description when taken in connection with the accompanying drawings, and the novel features thereof will be pointed outand clearly defined in the claim at the close of this specification. A

In the drawings, Figure 1 is a front elevation partly in section of a machine embodying the invention, the two press members being shown as in their separated position.

Fig. 2 is a vertical section on line 2-2 of F1g. 1, but showing the crank partially rotated from the position shown in Fig. 1 sufiiclent to bring the upper die into contact with the lower die.

Fig. 3 is a section taken on the same line as Fig. 2, but showing the crank still farther turned, being therein shown as at 180 from the position shown in Fig. 1.

Referring now to the drawings, 1 represents the base and 2 the upright portions of the frame. l/Vithin the uprights 2'there is ournaled a crank shaft 3 which may be operated in any suitable manner. Mounted on this shaft 3 are crank arms 4- 1 carry- I ing acrank pin 5. A pitman 6 is provided with a head 7 having a bearing through which passes the crank pin 5. This bearing is a broken or split bearinghaving a movable seat portion 8 which is movable with relation to the pitman head! and a cap portion 9 which is rigidly secured to the head portion 7 of the pitman.- The movable portion 8 is mounted in a recess 10 in the pitman head so as to be slidable longitudinally with relation to the head and is seated upon a spring 11.

The pitman 6 is connected by a screw 12 with the ra1n13 of the upper presser memher by any suitable coupling, the connection shown being a ball and socket joint, comprising a ball 14 seated in a socket 15 in the ram 13. Said screw 12 is adjustable with relation to the pitman 6 sothat the elevation of the upper presser member may be varied with relation to the lower presser member.

Connected with the lower end of the ram 13 is a die 16 or any other suitable presser device. As shown in the drawings there is secured to the under side of the die 16 a sweep, as shown in Fig. 2, the pitman' will be caused toedescend far enough to bring the upper. presser member or die 17 into pressing engagement with the blank which has been placed on top of the lower die, and if a cutter 20 such as shown in Fig. 2 is employed in connection with the upper die 17 it will also cut the blank for the article to be formed out of the blank sheet. At this stage of the movement the crank will have preferably moved through a trifle more than 90, that is it will have moved a little more than half-way to the bottom of its down ward stroke. During the continued movement 0]": the crank to the bottom of its down ward stroke, the crank pin 5 which rests upon the movable seat member 8 of the crank pin bearing will have pushed the said bearing downward upon the spring seat Ill, as allowed by the recess 10 in which the bearing member 8 is inelosed, and will compress the spring 11 as shown in Fig. 3. This not only produces an elastic pressure of the upper presser or die member 17 upon the blankwhich is seated upon the lower presser member or die, but it also causes a dwelling or": the upper presser member until in the continnedrotation the crank and the crank pin 5 will have swung up on the return stroke to a point at the same elevation as that at which the upper presser member was first brought into contact with the blank on the lower die. Then the upper presser member will begin to rise during the remainder of the upward stroke of the crank.

The spring ll. should be a poweriful spring, being strong enough to do the forming between the dies before the bearing member 8 begins to act to press the spring.

Having introduced the set 'of dies between the bolster 1S and the ram 13, and having set the ram'by means of the adjusting screw 12, it is obvious that when the downward action of the ram is arrested by the upper and lower dies coming together that the bearing 8 will still continue to let the crank travel and the dies will dwell together until the gap between the bearing and the slot in the head of the pitman is 7 closed and will continue to so dwell until the bearing 8 has returned to'its ori inal position, and the ram of the press starts its upward movement.

The action of the dwelling pitman as described is applicable to any press of the crank shaft type when the pressureon the piece to be formed would not have to exceed the capacity of the spring that could be in stalled in the head of the pitman. The dwell can be regulated by the size of the gap betweenthe bearing 8 and the head of the pitinan; the larger the gap, the longer the dwell. I

What I claimis:

In combination with a crank shaft, a cranlr'and a crank pin, a dwelling pitman carrying its lower end a presser member, and having a head formed with a slot er;- tending longitudinally in from the end thereof, and having an expansible bearing for the crank pin, said expansible bearing comprising two members ?separable from each other, each having a semi-cylindrical groove, the two grooves together forming a cylindrical bearing for the crank pin when the two semi bearing members are closed together one of said semi-bearing members being made fast to the end of the pitman and forming a captor he said slot, the other of said semi-bearing members being slidable in said slot toward and away from said fixed semi-bearing member to expand the bearing, and a spring held in a socket in the end of the pitnian which forms a seat for said slidable member and causes the presser member to exert a yielding pressure, and which is compressible to allow a dwell of the pitman while the crank pin continues a further downward movement.

In testimony whereof I affix my signature.

GEORGE P. MALLORY. 

